This invention relates to closures for containers, such as bottles, jars and similar screw-top containers. More particularly, the present invention is concerned with a form of reusable closure which includes a sealing member for sealing such containers against leakage of fluid from the container and against contamination by materials from outside of the container.
A container closure, which includes a threaded cap and a single piece gasket, is known from U.S. Pat. No. 2,980,276 entitled "Bottle Closure" and granted to Doria Nina Robineau on Apr. 18, 1961. The known closure includes an internal, centrally located stud of circular cross-section extending downwardly from the major, smooth, flat, interior surface defining the top of the cap. The gasket is made of resilient material, is of generally frusto-conical shape and has a central longitudinal sleeve which fits over the stud. The peripheral end of the gasket, when in place, is pressed against the smooth, flat interior surface of the cap, the center sleeve having been placed on the cap by slipping the sleeve on the stud. The gasket can thus be centered on the neck of the container and its peripherial end portion pressed between the rim surface of the container and the smooth, flat, interior surface of the cap. During opening and closing of the container, the gasket tends to turn or twist with respect to the cap, distinct shortcomings. This tendency of the gasket to turn or twist not only affects the sealing characteristics of the closure, but also results in wearing out of and distortion to the sealing portion of the gasket itself.
A closure for sealing a bottle or container which is similar to the container closure disclosed in the patent to Robineau, supra, is known from U.S. Pat. No. 3,462,034 entitled "Means for Closing and Sealing a Bottle or Container" issued to Arthur A. Friedberg on Aug. 19, 1969. The gasket in this instance is substantially flat with a centrally located, downwardly directed plug which, when the gasket and its associated cap are positioned over the neck of a container, extends into an opening of reduced diameter to seal the neck portion of the container from the body portion. The gasket tends to turn with respect to the cap during the opening and the closing of the container, in essence a disadvantage not unlike the shortcomings associated with closures of the type disclosed in the patent to Robineau, supra.
A proposed solution to the above-noted disadvantage of having the gasket or sealing member turn with respective to the cap or having the gasket twist during the opening and closing of a container, is to provide a cap (shell) and sealing member (fitment) as a unitary piece, the cap and sealing member being permanently fixed to one another. An example of this type of construction is disclosed in U.S. Pat. No. 4,489,844 entitled "Screw-Type All Plastic Closure" granted to Charles A. Breskin on Dec. 25, 1984. This known closure consists of a cap and gasket constructed of different plastic materials which are injection molded in different portions of the same molding cavity. The gasket or fitment is first formed and, thereafter, without moving the fitment, the cap or shell is formed to produce a unitary structure. While avoiding the shortcoming and disadvantage of relative turning between the cap and sealing member or twisting of the gasket, it is clear that the cap and gasket cannot be separated; consequently, when one of these elements becomes defective or wears out, both must be replaced, a disadvantage.
As representative of the general background in the closure arts involving screw-type caps or shells combined with gaskets or fitments, are six (6) U.S. Letters Patents identified as follows:
______________________________________ U.S. Pat. Nos. Inventor(s) Granting Dates ______________________________________ 2,917,198 Beall, Jr. 12/15/59, 3,053,407 Lowen 09/11/62, 3,129,809 Annen 04/21/64, 3,940,005 Granot 02/24/76, 4,394,923 Sugiyama 07/26/83, and 4,405,054 Braun et al. 09/20/83. ______________________________________
The closures for containers disclosed in the six (6) above-tabulated patents are similar, in relevant aspects, to those disclosed in the patents to Robineau, supra, and to Friedberg, supra, and can be characterized as having the disadvantage of having an insert or gasket which tends to turn or twist with respect to its associated screw-type cap during the opening and/or the closing of the container.